function fftStruct = doFFT(imageStruct)
    % Perform discrete fourier transform and quadrant shifting  
    fftStruct.fftImage = fftshift(fft2(imageStruct.image));
    
    
    % real and image components of fourier transform
    fftStruct.real = real(fftStruct.fftImage);
    fftStruct.imag = imag(fftStruct.fftImage);
    
    % Computes amplitude and phase
    fftStruct.module = sqrt(fftStruct.real.^2 + fftStruct.imag.^2);
    fftStruct.phase = atan2(fftStruct.imag, fftStruct.real);
    fftStruct.exists = 1;
end